Osteotomy plate, plate driver and method for their use

ABSTRACT

An orthopedic plate is specifically configured for use in osteotomies, in which part of the plate extends into a portion of a first bone segment and part is external to the cortical surface of an adjacent bone segment to fix the segments to allow them to fuse. The plate has a first end and a second end where the end which is inserted into the bone has a chamfer and a through hole having a hole axis optionally at an oblique angle to the longitudinal axis of the plate, and which can receive a screw, peg or pin. The second end of the plate includes a locking screw hole and optionally including a compression slot extending in a direction toward a screw hole in the opposing end. Optionally, the non-locking hole has a shroud that forms an arc or portion of a cylinder over the hole. A plate driver having a recess that holds the plate is used to insert the plate into the bone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/454,119, filed Jun. 27, 2019, which is a continuation of U.S. patentapplication Ser. No. 15/880,952, filed Jan. 26, 2018 (U.S. Pat. No.10,368,926), which is a continuation of patent application Ser. No.15/413,968, filed Jan. 24, 2017 (U.S. Pat. No. 9,888,949), which is adivision of U.S. patent application Ser. No. 14/625,657, filed Feb. 19,2015 (U.S. Pat. No. 9,572,607), which was a division of U.S. patentapplication Ser. No. 12/803,852, filed Jul. 8, 2010 (U.S. Pat. No.8,986,353), which claimed priority to U.S. Provisional Application No.61/270,486, filed Jul. 9, 2009 the entireties of which are hereinincorporated by reference.

FIELD OF THE INVENTION

The present invention relates to an orthopedic plate, which isconfigured for the fixation of a bone or bones of the foot, hand orwrist in particular following a procedure for fusion of adjacentsegments or reconstruction such as various osteotomy procedures. Theinvention also relates to a surgical driver that is used to implant theosteotomy plate and to a method for the use of the orthopedic plate andassociated driver in surgical reconstruction.

BACKGROUND OF THE INVENTION

The feet and the hands both include numerous bones and joints thatcooperate together to define quintessential human movement. They aresophisticated, delicate and altogether elegant in function and design.Together the foot and ankle have over 25 bones and 33 joints along withmore than 100 named muscles, tendons, and ligaments and a network ofblood vessels, nerves, all residing beneath a relatively slim coveringof soft tissue and skin. Structurally, the foot has three mainanatomical regions: the forefoot, the midfoot, and the hindfoot. Theseparts work together with the ankle, to provide the body with support,balance, and mobility. A structural flaw or malfunction in any one partcan result in the development of problems, which are manifested in otherareas of the body. The hand forms a cognate to the foot with 27 boneswithin the hand and wrist. There are eight small bones within the wristcalled the carpals, which join with the radius and the ulna to form thewrist joint. The carpals connect with the five metacarpals to form thepalm of the hand, which terminate in the rays (i.e., the thumb andfingers) formed by the phalanges. The three phalanges in each finger areseparated by two joints, called interphalangeal joints (IP joints). Theone closest to the MCP joint (knuckle) is called the proximal IP joint(PIP joint). The joint near the end of the finger is called the distalIP joint (DIP joint). The thumb only has one IP joint between the twothumb phalanges. The IP joints of the digits also work like hinges whenyou bend and straighten your fingers and thumb.

Similarly, the forefoot includes the five toes (which are also known asthe “phalanges”) and their connecting long bones (or “metatarsals”).Several small bones together comprise a phalanx or toe. Four of the fivetoes have three phalanx bones respectively connected by two joints. Thebig toe (or “hallux”) has two phalanx bones distal and proximal with ajoint in between called the interphalangeal joint. The big toearticulates with the head of the first metatarsal at the firstmetatarsophalangeal joint (the “MTP” joint) and there are two tiny,round bones called sesamoids on the plantar side of the metatarsal head.The phalanges are connected to the metatarsals at the ball of the foot.The forefoot balances pressure on the ball of the foot and bears asubstantial amount of the body weight.

The bones of the midfoot from medial to lateral are the 1^(st) through3^(rd) cuneiform, the cuboid, and the crescent shaped navicular boneposterior to the cuneiforms, which also forms a joint with the talusthat forms the basis for the ankle joint at the hinged intersection ofthe tibia, the fibula, and the foot. The five tarsal bones of themidfoot act together form a lateral arch and a longitudinal arch whichhelp to absorb shock. The plantar fascia (arch ligament) underlays thebones of the midfoot and along with muscles, forms a connection betweenthe forefoot and the hindfoot. The toes and their associated midfootbones form the first through fifth rays beginning with the great toe asthe first ray. The bones which form the palmate portion of the hand are:the scaphoid, the lunate, the triquetrum, the pisiform, the trapezium,the trapezoid, the capitate, and the hamate, which act in concert toallow the opposition of the thumb with each of the fingers and to permitthe uniquely human ability to manipulate objects.

The hindfoot is composed of three joints (subtalar, calcaneocuboid &talonavicular) and links the midfoot to the ankle. The heel bone (or“calcaneus”) projects posteriorly to the talus and forms a lever arm toactivate the hinged action of the foot so as to allow propulsion of theentire body from this joint. The calcaneus is joined to the talus at thesubtalar joint. The mid-foot is often the subject of trauma, such asresults from falls, vehicle crashes and dropped objects. These accidentsoften result in severe fractures and/or dislocations. In addition, thereare several conditions which result from congenital deformation or whicharise as a result of repeated use type injuries. Surgical interventionthat includes surgical sectioning of bone or an “osteotomy” is oftenused to restructure the bones as a treatment for such conditions. Forexample, the calcaneal translational osteotomy, with which the presentinvention might be used, is typically used to treat a condition that isthe result of adult acquired flatfoot deformity. The present inventionis likewise useful for conditions of the hand that result from priortrauma, surgical intervention or defects from birth or that develop withage (such as rheumatoid arthritis).

Examples of some of the other procedures with which the presentinvention could be used include hallus valgus and hallus rigiduscorrections, and bunionectomies. Other applications which could use thepresent invention include first and fifth metatarsal chevrons,translational osteotomies, closing wedge osteotomies, pediatric femoralosteotomies, metacarpal and calcaneal rotational osteotomies,intrarticular osteotomies and hand and wrist realignment osteotomies.

Typical surgical treatment of the foot or hand re-establishes a normalanatomy while the fractured bones mend. In some cases, fusion of a jointmay be necessary, for example, where arthritis arises in a patient dueto use injuries, poor bone or prior unsuccessful surgeries. One currentsurgical treatment of these conditions requires that pins, wires and/orscrews be inserted to stabilize the bones and joints and hold them inplace until healing is complete. For example, a pin or screw may beintroduced medially into the internal cuneiform and through the base ofthe second metatarsal bone. While the use of k-wires, pins, and screwsmay provide acceptable results for younger and more plastic patients,these methods of fixation are not always satisfactory.

SUMMARY OF THE INVENTION

In accordance with the present invention an orthopedic plate (as well asa driver for the plate) is provided which can be used to good advantagein an osteotomy. In a first embodiment, the plate has a footprint thatis a modified rectangle having a first end with rounded corners, and alongitudinally opposing end with a cutting edge that may include a taperor a crescent shape. Either two or three of the four sides of the plate,including both long sides and optionally the proximal end have a raisededge or rails which acts to stabilize the plate, and which is connectedwith a thinner flat web of material that includes one or more holes forscrews or pins. At the cutting end, the rails may terminate in pointedinsertion tips which are joined by the web that also includes a taperedcutting surface or the plate may simply include the tapered cuttingedge. In a second embodiment, the plate has a simple bar-like footprintwith a first end tab and a second end tab extending along thelongitudinal axis of the plate and with narrowed waist sections betweenthe tabs. At the first end tab, the plate includes a first portion thatis inserted into cancellous bone. This portion includes a rounded ortapered chamfered edge that promotes insertion into the bone. At thesecond end tab, the opposing portion includes a through hole so that theplate can be fixed to an extramedullary portion of an adjacent bonesegment. Optionally, the plate includes a compression or translationslot that extends in a direction and causes compression toward a throughhole in the opposing cancellous tab. The width of the plate decreasesbetween the holes to allow for bending if desired. In other embodiments,the footprint may by more “organic” in shape, with a rounded taperedinsertion surface, a mid-section that flares to accommodate an angledscrew hole and a rounded rear section that includes a secondperpendicular screw hole. In a further modification of this plate, theplate advantageously includes an angled hole with a shroud that protectsthe soft tissue from the head of the screw and which aids in optimalcompression of the posterior fragment for certain procedures.

The invention can be used in a variety of indications including forexample, calcaneal osteotomies Dwyer osteotomy, cotton osteotomy,isolated TMT fusion, Navicular fracture, Evans osteotomy and metacarpalrotational osteotomies, or intrarticular osteotomies or hand and wristrealignment osteotomies. Other applications which could use the presentinvention include first and fifth metatarsal chevrons, translationalosteotomies, and closing wedge osteotomies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a medial view of a foot with an orthopedic plate inaccordance with a first embodiment of the invention positioned for usein a translational calcaneal osteotomy procedure;

FIG. 1 b is a medial posterior view of a foot with a further embodimentof the plate of the present invention also for use in a translationalcalcaneal osteotomy procedure;

FIG. 2 is a top view of the orthopedic plate of FIG. 1 ;

FIG. 3 is a side view of the plate shown in FIG. 2 ;

FIG. 4 is an end view of the plate shown in FIG. 3 ;

FIG. 5 is a top perspective of the plate shown in FIG. 2 ;

FIG. 6 is an end perspective of the plate shown in FIG. 2 ;

FIG. 7 is a bottom perspective of the plate shown in FIG. 2 ;

FIG. 8 is a side perspective of the plate shown in FIG. 2 ;

FIG. 9 is a top view of a second embodiment of the orthopedic plate ofthe present invention;

FIG. 10 is a side view of the plate shown in FIG. 9 ;

FIG. 11 is an end view of the plate shown in FIG. 10 ;

FIG. 12 is a top perspective of the plate shown in FIG. 9 ;

FIG. 13 is an end perspective of the plate shown in FIG. 9 ;

FIG. 14 is a bottom perspective of the plate shown in FIG. 9 ;

FIG. 15 is a side perspective of the plate shown in FIG. 9 ;

FIG. 16 is a top view of a third embodiment of the orthopedic plate ofthe present invention;

FIG. 17 is a side view of the plate shown in FIG. 16 ;

FIG. 18 is an end view of the plate shown in FIG. 17 ;

FIG. 19 is a top perspective of the plate shown in FIG. 16 ;

FIG. 20 is an end perspective of the plate shown in FIG. 16 ;

FIG. 21 is a bottom perspective of the plate shown in FIG. 16 ;

FIG. 22 is a side perspective of the plate shown in FIG. 16 ;

FIG. 23 is a side perspective of the fourth embodiment of the orthopedicplate of the present invention;

FIG. 24 is a side perspective of the fifth embodiment of the orthopedicplate of the present invention;

FIG. 25 is a side perspective of the plate driver of the presentinvention;

FIG. 26 is a top view of the plate driver shown in FIG. 25 ;

FIG. 27 is a side view of the plate driver shown in FIG. 25 ;

FIG. 28 is a bottom view of the plate driver shown in FIG. 26 ;

FIG. 29 is a first end view of the plate driver shown in FIG. 25 ;

FIG. 30 is a second end view of the plate driver shown in FIG. 25 ;

FIG. 31 is a bottom perspective of the plate loosely attached to theplate driver in accordance with the invention;

FIG. 32 is a side view of the plate and driver in accordance with theinvention during insertion;

FIG. 33 is a side view of the plate and driver in accordance with theinvention during insertion;

FIG. 34 is a side view of a non-locking screw in accordance with theinvention;

FIG. 35 is a side view of a locking screw in accordance with theinvention; and

FIG. 36 is a side view of a variable locking screw in accordance withthe invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a skeletal version of a foot from the lateral side with aparticularly preferred embodiment of the plate 210 of the presentinvention in place between the junction of the talus and the calcaneuswith an angled screw inserted into the Sustentaculum Tali. Thus, FIG. 1illustrates the plate used in a translational osteotomy of the calcaneusfor treatment of flatfoot syndrome. Similarly, it can be used forfixation of other bone segments following osteotomies as previouslymentioned.

As viewed from the top in FIG. 2 , it can be seen that the firstembodiment of the plate 10 has a rectangular shape with a first end 12and an opposing cutting end 14 aligned along the longitudinal axis ofthe plate. The peripheral edges 16 of the plate are raised on threesides, including the two long sides 18, 19 and the squared short wall20. These edges form rails that help to provide stability for the plateand in particular to inhibit torsion of the plate during insertion andduring the recuperation period in which the injury fuses. The rails arerounded at the corners of the squared short wall 20. The opposing shortwall includes a chamfered cutting surface 22, which is illustrated as acrescent shape between the two forward extending insertion tips 24 thatare coextensive with the long wall edges. The body of the plate isformed by a thinner flat web 25 that extends between the raised edgesand includes a number of openings. Preferably, the web 25 includes afirst opening 26, or hole in the portion of the plate which extends intothe bone and which accepts a screw or a pin in order to help hold theplate in place and to keep it from rotating within the bone. Rearward ofthat, and somewhere beyond halfway along the long axis of the plate, theplate includes a compression slot 27 that accepts a screw to causecompression toward the first opening. Typically, the compression slotincludes a shoulder 28 along its internal edge 29 that slopes in thedirection that compression occurs. In the rearward portion, toward thesquared end, the plate includes a locking hole 30 which includes amechanism to cause locking, such as internal threads that mate withexternal threads on the head of a locking screw to lock this portion ofthe plate to the extramedullary portion of an adjacent bone fragment.

In a second embodiment, the plate 110 has a simple bar-like profile thatis comprised of a first end with a tab and a second end with a longertab. The longer tab 112 has a rounded end at its proximal end that necksin slightly into the body of the first tab 112, and the rounded endincludes a deep chamfer 115 which tapers from the lateral edge of theplate to an optional through hole 116 which can receive a screw or pinthat helps to secure the plate in the cancellous portion of the boneagainst rotation or movement. The longer tab also includes an obroundtranslation or compression slot 120 at the distal end of the first tab.The plate width flairs slightly around the slot to preserve the metalwhich defines the slot (preferably to reinforce the slot to inhibitdeformation of the slot during any option bending procedures, or evenduring insertion. Again the plate necks in slightly at the transitionbetween the first tab and the second tab and the distal most 114 of thepair of tabs includes a screw hole 122 (which preferably includeslocking means such as internal threads or a variable locking mechanism,so as to form a locking interface between the plate and the respectivebone or bone fragment by means of the rigid fastening of the screw inthe screw hole in the plate.) The locking hole optionally furtherincludes keyways for a drill guide. The compression slot is configuredso as to cause compression along the longitudinal axis of the plate inthe direction of the locking screw hole. The plate includes incurvatures123 between the openings to form waist sections that minimize thematerial used and maximizes the fit of the plate, as well as allowingadditional contouring of the plate in these areas, should it be desired.

In a third embodiment, the plate 210 corresponds in shape and functionto the second embodiment. Specifically it has a first rounded tab endhaving a deep chamfer that permits the plate to be inserted into boneand a second rounded end having a threaded locking screw hole. In thisembodiment, the compression slot is replaced by an angled non-lockingscrew hole 220 which includes a hole shroud 222 forming an arc or aportion of a cylinder raised above the top surface of the body of theplate in order to sufficiently support the screw that is received inthis hole and to shroud the head of the screw to help minimize thepossibility of soft tissue irritation that the screw head mightotherwise provide. The shroud also provides some support and compressionwithin the bone into which it projects. The non-locking hole is angledso that the axis of the screw forms an angle of about 10° to about 45°,and preferably about 15° to about 40°, and more preferably about 25° toabout 35° to the longitudinal axis and the hole allows for about 30°,preferably about 20°, and most preferably about 15° of conical rotationof the screw within the screw hole of the plate which is provided toenable the surgeon to capture the sustentaculum. This screw is intendedto capture the anterior portion of the calcaneus in a calcanealosteotomy.

FIGS. 3 and 4 illustrate the edge on views of the first embodiment ofthe plate in along a first length and along the second shorter length,which is perpendicular to the first length. As can be seen the web ofthe plate has a generally uniform thickness between the inward surface27 which opposes and optimally, but not necessarily engages the bones,and the outward surface 29. Similarly, the second embodiment isillustrated in edge on views in FIGS. 10 and 11 in which it can be seenthat this embodiment that the plate is flat and of a uniform thicknessbetween the bone-facing surface of the cortical portion of the plate.Optionally, the inward surface 127 of the plate 110 could includes agenerally uniform radius of curvature along the longitudinal axis sothat the plate would have the shape of a segment of a cylinder whichmaximizes the ability to place the plate as desired without the need foradditional pre-surgical contouring for certain applications, althoughthe plate thickness allows for bending if necessary Also optionally forthis design, the distal edge of the plate can be of a larger radius orthicker width to provide a broader shoulder 136 so that the proximalportion of the plate can be driven into the bone.

FIGS. 23 and 24 illustrate other embodiments 310, 410 of the orthopedicplate of the present invention that illustrate how different features ofthe previous embodiments could be combined, including the straight tapercutting edge, and with the compression slot or with the angled screwhole and shroud.

FIGS. 25 through 30 illustrate the plate driver 500 of the presentinvention. The driver 500 includes a plate holder portion 510, which hasat one end a recess or pocket 515 that captures the end of the plate 600(see FIG. 31 ) having the locking hole. Specifically, the plate holder510 includes a knob 517 joined to a shaft 518 that is journaled within abore 519 in the plate holder 510. The end of the shaft 518 includesthreads that can engage the internal threads of the locking hole in theplate to hole the plate within the plate holder as well as relative tothe plate driver. The plate driver further includes a handle 520 thatallows the surgeon to hold the plate driver. The plate holder portionholds the plate with the long axis in line with the long axis of thehandle, but offset from the plate which gives the surgeon bettervisibility to the surgical site. Further, the handle 520, includesfenestrations 522 which lighten the weight of the plate driver, and atthe end of the handle, there is a buttressed area 525, which has a widerflat surface that can be used to tap the plate into the bone. FIGS. 32and 33 illustrate a plate 600 being inserted into the cortical sectionof a calcaneus using the plate driver 500.

The screws useful with the plate of the present invention areself-starting, self-tapping screws including the option of partial orfull cannulation. The screws include a cutting 142 end having multipleflutes 144, and preferably 2 or 3 flutes about a conical recess. Thescrews further include a partial taper 132 of the inner diameter in theproximal end over the first several thread turns, for example over 2-8,and preferably over 3-5 turns in order to increase the fatigue life ofthe screw as well as providing potential physiological advantages inuse. The screws further include a torque driving recess. The screws 120,140, 150 have a threaded distal end and a head including a torquedriving recess 156. The head of the locking screw includes lockingmeans, such as a variable locking mechanism 160, which could be abushing that mates with the screw head so as to lock the screw relativeto the plate at a desired angle, or could include external screw threads134 that mate with internal threads in the locking screw hole at apre-selected angle, in this instance, the screw axis is perpendicular tothe longitudinal axis of the plate. The screw used in the compressionslot has a rounded rear shoulder (such as a hemisphere, or a toroid)which mates with the concavely rounded groove of the compression slot soas to maximize surface contact between the screw head and the inclinedgeometry of the compression slot. The lateral edge of the compressionslot further includes an inclined shoulder that slopes downward towardthe bone-contacting surface of the plate and which is engaged by thescrew head to cause the translation of the screw and attached bonefragment along the long axis of the slot and towards the locking hole.

The plate is formed of a biocompatible material, and preferably a metalsuch as surgical grade stainless steel, titanium or a titanium alloy ora cobalt chromium alloy. Preferably, the plate web has a thickness ofbetween about 1.0 and about 2.5 millimeters, more preferably betweenabout 1.5 and about 2 millimeters, and most preferably between about 1.5and about 1.8 millimeters. The plate includes a raised continuous outeredge 16 which is defined between the top and the bottom surface andwhich has a total thickness of about 2 and 5 millimeters, or roughlytwice the width of the web portion of the plate.

In addition, the plate can include a small through hole sized to receivea K-wire or other similar guide wire.

During the surgery the joints are first prepped which may includede-articulation between the bones to be fused and removal of any bone aspart of the osteotomy, and as necessary, the plate is bent to contour tothe bone surface. A pilot hole may be drilled into the bone into whichthe plate will be inserted. The plate is inserted into the plate recessin the plate driver and secured by tightening the plate upward in theplate holder using the plate holder having an end that has threads whichmate with the locking threads of the locking hole in the plate. Theplate is tamped into the cancellous portion of the bone fragmentoptionally by tapping the plate driver with a one pound mallet as isnecessary to insert the plate. The plate should be driven until therecess or pocket makes contact with the anterior portion of thecalcaneus. Once the plate is sunk, a drill guide is mated to the platedrive, and a hole is drilled for the locking screw. The plate can beheld in position using olive wires (thru the non-locking hole and intothe bone). The plate is located such that all of the screws are aimedinto the targeted bones and away from the joint, fracture, or boneinterface. The olive wire is removed if used, and a pilot hole isdrilled at the end of the plate that includes the first hole and thishole is pinned or screwed. A second pilot hole may be drilled for thenon-locking screw at the desired angle given an optional 15° of conicalrotation within the non-locking hole and a non-locking screw is insertedinto this pilot hole and tightened. As the screw is tightened in theangled hole, it will drive compression toward the fusion site and thefirst hole. The plate allows for up to 1.5 millimeters of compression.Finally, a pilot hole is drilled in the cortical surface of the secondbone fragment, for example using a drill guide such as a guide includingkeyway guides (i.e. lobes) that interlock with corresponding keywayopenings in the locking screw hole and a locking screw is secured inthis hole. The plate is viewed radiographically, and the soft tissuesare closed in the usual manner.

This invention has been described in detail with reference to specificembodiments thereof, including the respective best modes for carryingout each embodiment. It shall be understood that these illustrations areby way of example and not by way of limitation.

What is claimed is:
 1. A plate for bone fixation comprising: a firstend; a second end with a deep chamfer which tapers from a lateral edgeof the plate; a bottom surface configured for contact with a bone; a topsurface spaced-apart from the bottom surface, wherein an open-endedpassageway communicates between the top surface and the bottom surface,the open-ended passageway being defined in offset relation to at leastone of the top surface and the bottom surface, with a portion of the topsurface circumferentially adjacent a top open-end of the passageway thatis configured to receive a head of a screw within an angle of rotationof up to 20°; and a shroud extending outward from the top surface at anoblique angle and covering at least a portion of the top open-end, theshroud adapted to be interposed between a tissue and the head of thescrew so as to prevent tissue irritation and provide compression to thebone.
 2. The plate of claim 1, wherein the plate has a distal edgehaving a larger thickness to provide a broader shoulder so as to allowfor the proximal portion of the plate to be driven into a bone.
 3. Theplate of claim 1, further comprising a compression slot passagewaycommunicating between the top surface to the bottom surface.
 4. Theplate of claim 1, wherein an axis of the passageway forms an angle ofbetween 10° and 45° with the top surface.
 5. The plate of claim 1,wherein an axis of the passageway forms an angle of between 15° and 40°with the top surface.
 6. The plate of claim 1, wherein an axis of thepassageway forms an angle of between 25° and 35° with the top surface.7. The plate of claim 1, wherein a cutting edge is formed at the firstend.
 8. A plate for bone fixation comprising: a bottom surfaceconfigured for contact with a bone; a top surface arranged inspaced-relation to the bottom surface, wherein an open-ended passagewayis defined between the top surface and the bottom surface sized topermit a screw to be inserted therethrough with a less than 90° anglebetween a screw axis and a passageway axis to allow for a conicalrotation of the screw, the passageway configured to receive a head ofthe screw wherein the passageway axis forms an angle with respect to thebottom surface between 10° and 45°; and an arcuate shroud projectingoutwardly from the top surface at an oblique angle and covering at leasta portion of an open-end of the passageway, the shroud adapted to beinterposed between a tissue and the head of the screw.
 9. The plate ofclaim 8, wherein the angle of the passageway axis with respect to thebottom surface is between 15° and 40°.
 10. The plate of claim 8, theangle of the passageway axis with respect to the bottom surface isbetween 25° and 35°.
 11. The plate of claim 8, further comprising asecond open-ended passageway is defined through the plate thatcommunicates between the top surface and the bottom surface.
 12. Theplate of claim 8, further comprising a tapered crescent-shaped cuttingedge.
 13. A plate system for use in associated bone comprising: anon-locking screw having distal threads and a head having a roundedsurface without external threads; and a plate having: a first end and asecond end with a longitudinal axis defined between the first end andthe second end; a bottom surface configured for contact with a bone; atop surface spaced-apart from the bottom surface, wherein an open-endedpassageway communicates between the top surface and the bottom surface,the open-ended passageway being defined in offset relation to at leastone of the top surface and the bottom surface, with a portion of the topsurface circumferentially adjacent a top open-end that is configured toreceive the head of non-locking screw within an angle of rotation of upto 20°; and a shroud projecting outwardly from the top surface at anoblique angle and covering at least a portion of the top open-end, theshroud adapted to minimize interaction between a tissue and the head ofa non-locking screw.
 14. The plate of claim 13, wherein the plate has adistal edge having a larger thickness to provide a broader shoulder soas to allow for the proximal portion of the plate to be driven into abone.
 15. The plate of claim 13, wherein the passageway is shaped so asto permit the screw to be inserted therethrough with an angle between ascrew axis and a passageway axis of up to 20° of conical rotation. 16.The plate of claim 13, wherein an axis of the passageway forms an angleof between 10° and 45° with the top surface.
 17. The plate of claim 13,wherein an axis of the passageway forms an angle of between 25° and 35°with the top surface.
 18. The plate of claim 13, wherein a straighttaper cutting edge is formed at the first end.